I had an Iphone 4 that AT&T just unlocked for me. Unfortunately, the battery stopped charging and I returned it to Apple and got a replacement ($149). I asked if it was unlocked and they said I would have to do that with AT&T again. Anyway, I got home and activated it. I popped in my T-Mobile sim and it worked! The phone came with 5.0.1. After the jailbreak I had "no service". I restored the phone, which bumped it up to 5.1 and still had the "no service". I put my old AT&T sim in and their name and bars appear. Any ideas how to fix this? Strange that a new phone was already unlocked and then the jailbreak undone that. I also called AT&T and gave them the IMEI number. She said it wasn't eligible, so I explained the story and she put in the request anyway.